Spotted Wing Drosophila Alert — September 5, 2025
David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist, Phil Fanning, Assistant Professor of Agricultural Entomology, Christina Howard, Maine New Farmers Project Manager
Spotted wing drosophila fruit fly trap counts were little changed from last week. Sites that are no longer spraying because harvest is complete are seeing higher numbers than sites that are still harvesting and spraying to protect the remaining crop (see table below). We still expect that populations will further increase as we see some relief from present drought conditions. Growers with late ripening fruit such as fall fruiting raspberries, late ripening blueberries and day neutral strawberries should monitor their plantings closely for flies, and regularly check fruit for larvae. A 5 to 7-day spray schedule on ripening fruit may be required to keep it in good, marketable condition.
If you are growing raspberries, blackberries and/or blueberries, you should be managing spotted wing drosophila on any fruit that is presently ripening and/or being harvested to prevent infestation.
For more information on identifying spotted wing drosophila (SWD) and updates on populations around the state, visit our SWD blog.
Other IPM Web Pages
Michigan State University Spotted Wing Drosophila
Penn State University Spotted Wing Drosophila Overview
University of New Hampshire SWD Weekly IPM Reports
David T. Handley
Vegetable and Small Fruit Specialist
Highmoor Farm
P.O. Box 179
Monmouth, ME 04259
207.933.2100
UMaine Extension Diagnostic Research Lab
Pest Management Unit
17 Godfrey Drive
Orono, ME 04473
1.800.287.0279
| Town | SWD weekly trap catch 8/15/25 | SWD weekly trap catch 8/22/25 | SWD weekly trap catch 8/29/25 | SWD weekly trap catch 9/5/25 |
|---|---|---|---|---|
| Wells | 135 | 323 | 468 | 341 |
| Springvale | 67 | 201 | 1720 | 654 |
| New Gloucester | 190 | 57 | 128 | 69 |
| Cape Elizabeth | 474 | 388 | 695 | 798 |
| Bowdoinham | 27 | 103 | 139 | 141 |
| Mechanic Falls | 86 | 115 | 220 | 71 |
| Monmouth | 40 | 24 | 30 | 13 |
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